The present invention relates to water heating systems and more particularly to a water heating system in which there is a recycling of water to increase the thermal efficiency of the system.
Water heating systems have been widely used for many years and take many forms. A typical system is disclosed in U.S. Pat. No. 3,341,122 issued Sept. 12, 1967 to A. Whittel, Jr. In this earlier system a boiler is provided from which flue gases are discharged, water is introduced into the boiler under pressure, and an air separation tank receives heated water from the boiler and from which hot water is extracted for the intended uses. A double set of concentrically wound coils is provided within the air separation tank through which water to be used for various purposes is circulated in heat exchange relation with the heated water from the boiler being deairated in the air separation tank. However, it will be recognized that since the heat exchange is dependent upon the temperature and auantity of water fed to the tank from the boiler, in order to obtain a steady supply of heated water from the coils the boiler must be regulated to constantly provide a sufficient quantity of hot water. This entails operation of the boiler under conditions requiring increased fuel consumption. Concomitantly the hot flue gases being discharged are wasted as a source of heat exchange.